Polishing device

ABSTRACT

A polishing device is provided with an expandable or contractible polishing body. The polishing device is further provided with a polishing mechanism that includes: a pressing force applying mechanism that applies a pressing force to the polishing body; and a supporting body that supports the pressing force applying mechanism. Moreover, the pressing force applying mechanism is configured to include an advancing or retracting section capable of advancing or retracting, and a swinging section provided in a swingable manner to a tip of the advancing or retracting section, the tip facing the polishing body.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-194182 filed on Oct. 15, 2018, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a polishing device that polishes an object-to-be-polished by a polishing body.

Description of the Related Art

A polishing body for polishing an object-to-be-polished is usually configured as a disk-shaped rotating body as exemplified in Japanese Laid-Open Patent Publication No. 2004-009189. However, in this case, although it is possible for a flat surface to be polished, it is not easy for an irregular surface where undulations are present to be uniformly polished.

Accordingly, providing the polishing body with an elastic body (a cushion), for example, a sponge, is envisioned. This is because in this case, the elastic body is crushed when polishing a projection of the object-to-be-polished, whereas the crushed elastic body attempts to return to its original shape when polishing a recess of the object-to-be-polished. Thus, since a shape following ability is manifested in the polishing body by the elastic body, it is conceivably made possible for the irregular surface to be comparatively easily polished.

SUMMARY OF THE INVENTION

In fact, the shape following ability of the elastic body is not particularly favorable. Therefore, in the case where, for example, regarding a region-to-be-polished having a complex shape of the kind where a projection and a recess are alternately aligned, it is attempted to polish the projection of the region-to-be-polished, the elastic body may sometimes be insufficiently crushed. When such a situation occurs, a polishing amount with respect to the projection will be larger than a design value.

In order to avoid this, often, when the region-to-be-polished has a complex shape, polishing is performed manually by an operator. However, this case is troublesome and a burden for the operator.

A main object of the present invention is to provide a polishing device capable of performing automatic and favorable polishing, even in such a case as when a region-to-be-polished has a complex shape.

Due to an embodiment of the present invention, there is provided a polishing device that polishes an object-to-be-polished by an expandable or contractible polishing body, the polishing device comprising:

-   -   a pressing force applying mechanism configured to apply a         pressing force to the polishing body; and     -   a supporting body configured to support the pressing force         applying mechanism,     -   the pressing force applying mechanism including an advancing or         retracting section configured to advance or retract, and a         swinging section provided in a swingable manner to a tip of the         advancing or retracting section, the tip facing the polishing         body,     -   the polishing device further comprising a control section         configured to control a propelling force applied to the         advancing or retracting section.

In the present invention, when the supporting body eccentrically rotates so that the polishing body makes sliding contact with (performs polishing of) the object-to-be-polished, the advancing or retracting section configuring the pressing force applying mechanism that applies the pressing force to the polishing body advances or retracts, or the swinging section swings. Due to the advancing or retracting section and the swinging section operating in this way, the polishing body makes sliding contact with a region-to-be-polished, while suitably expanding/contracting and applying an appropriate and substantially uniform surface pressure to the region-to-be-polished. It therefore becomes possible for automatic and favorable polishing to be implemented.

The polishing device is preferably provided with an eccentric rotation unit configured to eccentrically rotate the supporting body. When the supporting body is eccentrically rotated, the pressing force applying mechanism supported by the supporting body also eccentrically rotates. Therefore, a polishing force transmitted to the object-to-be-polished via the polishing body becomes wide-ranging, so a polishable region becomes wide-ranging.

In addition, the polishing device is preferably provided with a tension applying unit configured to apply a tension to the polishing body. By using the tension applying unit to regulate the tension applied to the polishing body, the surface pressure on the region-to-be-polished of the polishing body can be suitably changed.

In the pressing force applying mechanism, the advancing or retracting section advances or retracts, or the swinging section swings, according to a shape of the region-to-be-polished, for example. Due to the advancing or retracting section and the swinging section operating in this way, automatic and favorable polishing can be implemented, even when the region-to-be-polished has a complex shape.

The polishing device preferably comprises a robot configured to hold the supporting body. In this case, by storing in the robot (teaching the robot) a locus of movement of a polishing mechanism, polishing can be continuously and automatically implemented on a more wide-ranging region-to-be-polished than the polishing body. Furthermore, as well as it being possible for the polishing mechanism to be moved following a shape of the object-to-be-polished even when the object-to-be-polished has a complex shape, polishing can be performed and completed in a short time.

The advancing or retracting section can be configured from an air cylinder having a rod, for example. In this case, a configuration of the advancing or retracting section can be simplified, and compactification and weight-lightening can be achieved.

Moreover, the polishing body can be configured from an endless belt configured to turn. In this case, a driving force applying unit configured to apply, to the endless belt, a driving force for turning may be provided. Since an unspecific place of the endless belt thereby makes sliding contact with the region-to-be-polished, it can be avoided that a specific place of the endless belt is worn down early.

Alternatively, a sheet body hooked to the supporting body may be adopted as the polishing body. In this case, there is no specific need to provide a driving force applying unit for turning the sheet body, so the polishing mechanism can be simplified.

A polishing start point is a movement start point of the polishing mechanism, and a polishing end point is a movement end point of the polishing mechanism. Therefore, at the polishing start point and the polishing end point, a sliding contact force of the polishing body when making sliding contact with the region-to-be-polished is reduced. Accordingly, it is preferable that by control of the control section, the propelling force applied to the advancing or retracting section at the polishing start point and the polishing end point for the object-to-be-polished is set larger than the propelling force applied to the advancing or retracting section at another region-to-be-polished. Due to configuring in this way, a polishing amount will be sufficient even at the polishing start point and the polishing end point. As a result, polishing unevenness can be avoided.

Due to the present invention, it is arranged that the pressing force applying mechanism for applying the pressing force to the polishing body is configured to include the advancing or retracting section that advances or retracts, and the swinging section provided in a swingable manner to the tip facing the polishing body of the advancing or retracting section. The advancing or retracting section advances or retracts, or the swinging section swings, whereby the polishing body suitably expands/contracts. Hence, the polishing body makes sliding contact with the region-to-be-polished while applying an appropriate and substantially uniform surface pressure to the region-to-be-polished. This makes it possible for automatic and favorable polishing to be implemented.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which preferred embodiments of the present invention are shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic overall side view of a polishing device according to a first embodiment of the present invention;

FIG. 2 is a schematic side view of a polishing mechanism configuring the polishing device;

FIG. 3 is a schematic plan view of the polishing mechanism;

FIG. 4 is a schematic front view of the polishing mechanism;

FIG. 5 is a schematic cross-sectional front view of a pressing force applying mechanism;

FIG. 6 is a schematic explanatory drawing showing a movement locus of the polishing mechanism on a workpiece being an object-to-be-polished;

FIG. 7 is a schematic plan view showing one example of an attitude of the pressing force applying mechanism when a recess is present in a region-to-be-polished;

FIG. 8 is a schematic plan view showing one example of the attitude of the pressing force applying mechanism when a projection is present in the region-to-be-polished;

FIG. 9 is a schematic plan view of a polishing mechanism configuring a polishing device according to a second embodiment of the present invention;

FIG. 10 is a schematic cross-sectional front view of a pressing force applying mechanism; and

FIG. 11 is a schematic plan view of the polishing mechanism when an advancing or retracting section has advanced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of a polishing device according to the present invention will be presented and described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic overall side view of a polishing device 10 according to a first embodiment. This polishing device 10 comprises: an articulated robot 12; a polishing mechanism 16 provided to a tip arm 14 configuring the articulated robot 12; and a control section 20 that controls the articulated robot 12 and the polishing mechanism 16. Note that the reference symbol 22 in FIG. 1 indicates a workpiece being an object-to-be-polished. An automobile body may be cited as a specific example of the workpiece 22.

The articulated robot 12 includes a rotatable pedestal 24 and a plurality of shaft sections 26, hence is capable of moving the polishing mechanism 16 to a certain place of the workpiece 22, and displacing the polishing mechanism 16 along a region-to-be-polished of the workpiece 22.

As shown in FIGS. 2 and 4, the polishing mechanism 16 is coupled to the tip arm 14 via a coupling plate 30. A gear holding plate 32 of narrower width and smaller area compared to the coupling plate 30 is close to the coupling plate 30. This gear holding plate 32 is provided with a gear train. Specifically, the gear train includes: a driving gear 38 provided to a driving shaft for eccentricity 36 of a motor for eccentric rotation 34 (an eccentric rotation unit); a first driven gear 40 engaged with the driving gear 38; and a second driven gear 42 engaged with the first driven gear 40. The second driven gear 42 is provided with a driven shaft for eccentricity 44.

The driving shaft for eccentricity 36 and the driven shaft for eccentricity 44 are passed through shaft insertion holes (not illustrated) respectively formed in the gear holding plate 32 and the coupling plate 30. A first rotating shaft for eccentricity 48 and a second rotating shaft for eccentricity 50 are respectively coupled, via eccentric joints 46, to tips of the driving shaft for eccentricity 36 and the driven shaft for eccentricity 44, the tips being on a side facing the polishing mechanism 16 and projecting from the coupling plate 30. An eccentric rotation mechanism 52 for eccentrically rotating the polishing mechanism 16 is configured as above. Note that an unillustrated bearing is inserted between the shaft insertion hole and the driving shaft for eccentricity 36 or driven shaft for eccentricity 44.

The first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are coupled to a supporting body 60 configuring the polishing mechanism 16. Specifically, as shown in FIGS. 2 and 4, the supporting body 60 is configured by combining: a motor holding wall section 62 whose height is greatest; a first side wall section 64 that supports a rear surface of the motor holding wall section 62 and has a region that inclines downwardly as the first side wall section 64 is separated from the motor holding wall section 62; a second side wall section 66 whose height is substantially half that of the motor holding wall section 62; and a mechanism holding wall section 68 bridged between the first side wall section 64 and the second side wall section 66. The first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are coupled to the upper side of the motor holding wall section 62 among these wall sections. In this case, the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are arranged along a longitudinal direction of the motor holding wall section 62.

In this way, the tip arm 14 of the articulated robot 12 holds the supporting body 60 configuring the polishing mechanism 16, via the coupling plate 30 and the eccentric rotation mechanism 52. Note that as may be understood from the above, the first side wall section 64 and the second side wall section 66 have their one ends coupled to the motor holding wall section 62 and have their other ends coupled to the mechanism holding wall section 68. The mechanism holding wall section 68 is separated by a predetermined distance from the motor holding wall section 62, by the first side wall section 64 and the second side wall section 66 interposed between the mechanism holding wall section 68 and the motor holding wall section 62.

As shown in FIG. 2, a motor for turning 72 (a driving force applying unit), which applies a driving force for turning an endless belt 70 serving as a polishing body configuring the polishing mechanism 16, is attached to the motor holding wall section 62 at a position not interfering with the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50. A long columnar driving pulley 76 is fitted over a driving shaft for turning 74 of the motor for turning 72. The driving pulley 76 drives the endless belt 70.

The supporting body 60 is provided with three bearing sections not illustrated. As shown in FIG. 3, the bearing sections each axially support in a rotatable manner a supporting shaft 80 provided to a long columnar driven pulley 78. Each of side peripheral walls of the driven pulleys 78 also drive the endless belt 70. Due to the driving pulley 76 and the three driven pulleys 78, the endless belt 70 is stretched so as to have a rectangular shape in planar view.

The endless belt 70 is formed of a stacked body of an inner peripheral belt 82 and an outer peripheral belt 84. The inner peripheral belt 82 is made of a material excelling in wear resistance, and the outer peripheral belt 84 is made of a material excelling in polishing performance. Due to the inner peripheral belt 82 being driven by the driving pulley 76 and the driven pulleys 78, the outer peripheral belt 84 turns integrally with the inner peripheral belt 82. The outer peripheral belt 84 makes sliding contact with the region-to-be-polished of the workpiece 22.

An exterior tensioner 86 (a tension applying unit) makes sliding contact with the outer peripheral belt 84. The exterior tensioner 86 presses the outer peripheral belt 84 toward the inner peripheral belt 82 side, and thereby applies a tension to the endless belt 70. The larger the pressing force is, the more the endless belt 70 is tensioned, and, as a result, the larger the tension applied to the endless belt 70 becomes. Conversely, when the pressing force is small, the tension applied to the endless belt 70 is reduced.

The mechanism holding wall section 68 supports a plurality of pressing force applying mechanisms 90 that press the endless belt 70 from the inner peripheral belt 82 side. Next, this pressing force applying mechanism 90 will be described.

FIG. 5 is a schematic cross-sectional front view showing one pressing force applying mechanism 90 along the longitudinal direction thereof. The pressing force applying mechanism 90 includes: an air cylinder 92 configuring an advancing or retracting section; and a swinging section 94.

The air cylinder 92 includes a cylinder tube 98 to which a supply/discharge tube 96 is coupled. The cylinder tube 98 is held by the mechanism holding wall section 68, whereby the pressing force applying mechanism 90 is supported by the mechanism holding wall section 68.

An unillustrated piston is housed in the cylinder tube 98, and a pressing rod 100 that is displaced integrally with the piston is exposed on an outside of the cylinder tube 98. Furthermore, the mechanism holding wall section 68 is integrally attached to tips of all of the cylinder tubes 98. The mechanism holding wall section 68 has a plurality of rod insertion holes 102 (refer to FIG. 3), and the pressing rods 100 are passed through the rod insertion holes 102.

A tip of the pressing rod 100 is provided with a ball joint 104. That is, as shown in FIG. 5, a screw-shaped shaft section 106 of the ball joint 104 is screwed into a screw hole provided in the tip of the pressing rod 100. Moreover, an engaging shaft section 109 that projects from a ball section 108 joined to the screw-shaped shaft section 106, is fitted into an unillustrated bearing hole being one region on an interior of a swinging cover 110. The swinging cover 110 swings around the ball section 108 as the ball section 108 rolls relatively to the bearing hole. An end surface (a pressing surface 114), on a side facing the inner peripheral belt 82, of the swinging cover 110 is configured as a flat surface having a substantially square shape.

In addition, the swinging cover 110 includes two inclined sections 116 that are joined to end sections of the pressing surface 114 and are inclined so as to approach the pressing rod 100. Therefore, an external appearance of the swinging cover 110 is configured in a substantially isosceles triangle shape.

A predetermined number of the pressing force applying mechanisms 90 configured in this way are aligned so as to form a plurality of rows and a plurality of columns. That is, the plurality of pressing force applying mechanisms 90 are aligned not only in a surface direction of FIG. 2, but also in a direction orthogonal to a paper surface.

Note that the control section 20 controls the motor for eccentric rotation 34, the motor for turning 72, the exterior tensioner 86, and a supply/discharge mechanism (not illustrated) for performing supply/discharge of compressed air to/from the air cylinder 92 via the supply/discharge tube 96.

The polishing device 10 according to the first embodiment is basically configured as above, and the operational advantages thereof will be next described in relation to a control method (operation) of the polishing device 10.

In order to move the endless belt 70 along the region-to-be-polished in a state where the endless belt 70 has been abutted on the polishing start point of the workpiece 22, teaching is performed beforehand in the articulated robot 12 so that each of the shaft sections 26 rotates or revolves by a predetermined angle. In addition, among the plurality of pressing force applying mechanisms 90, regarding a pressing force applying mechanism 90 that, as a result of the teaching, has been determined not to enter the region-to-be-polished, the control section 20 maintains the pressing rod 100 in a state where the pressing rod 100 is positioned at a backward end. This is achieved by not supplying compressed air to the cylinder tube 98 from the supply/discharge mechanism.

For example, when implementing polishing on the workpiece 22 shown in FIG. 6, the polishing mechanism 16 is displaced in order of a section-A 120→a section-B 122→a section-C 124→a section-D 126 of the workpiece 22, due to the articulated robot 12 operating according to the teaching. That is, the section-A 120 is the polishing start point, and the section-D 126 is the polishing end point. In this case, in the section-A 120, one column, namely, a lowest column, in the section-B 122 and the section-C 124, two columns, namely, the lowest column and a column one above the lowest column, and in the section-D 126, three columns, namely, the lowest column and columns one and two above the lowest column, fall outside the region-to-be-polished. That is, the lowest column does not overlap the region-to-be-polished from the polishing start point to the polishing end point. Hence, in this case, compressed air is not supplied to the air cylinders 92 of the pressing force applying mechanisms 90 forming the lowest column.

When starting polishing, the control section 20 first controls the exterior tensioner 86. Specifically, the exterior tensioner 86 is displaced so as to approach the endless belt 70, and presses the endless belt 70. Due to this pressing, the endless belt 70 is tensioned so that the tension thereof increases. In addition, the control section 20 supplies compressed air from the supply/discharge mechanism to the air cylinders 92 configuring the pressing force applying mechanisms 90 other than the pressing force applying mechanisms 90 of the lowest column. The compressed air is introduced into the cylinder tube 98 via the supply/discharge tube 96, and presses the piston. As a result, the pressing rod 100 advances to a forward end, and the flat pressing surface 114 of the swinging cover 110 presses the endless belt 70 from the inner peripheral belt 82 side.

The shaft sections 26 of the articulated robot 12 each suitably operate, and the endless belt 70 abuts on the section-A 120. In the case where a projection 130 due to undulations or curvature is present in the section-A 120, the pressing force of the air cylinder 92 (the pressing rod 100) facing the projection 130 may be reduced, if required. This is achieved by discharging a small amount of compressed air from the cylinder tube 98 via the supply/discharge tube 96. By thus regulating (correcting) the pressing force from the pressing rod 100 according to the projection 130 (refer to FIG. 8) of the section-A 120, the section-A 120 can be evenly polished.

Next, the control section 20 drives the motor for eccentric rotation 34 and the motor for turning 72. In association with the rotation of the driving shaft for eccentricity 36 of the motor for eccentric rotation 34, the driving gear 38 rotates, and the first driven gear 40 (refer to FIGS. 2 and 4) engaged with the driving gear 38 and the second driven gear 42 engaged with the first driven gear 40, rotate. Following this, the driven shaft for eccentricity 44 also rotates.

As described above, the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are respectively coupled, via the eccentric joints 46, to the driving shaft for eccentricity 36 and the driven shaft for eccentricity 44. Hence, the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 move with loci of circles centered on respective rotation centers of the driving shaft for eccentricity 36 and the driven shaft for eccentricity 44. As a result, the polishing mechanism 16, in which the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are coupled to the supporting body 60, eccentrically rotates.

Moreover, when the motor for turning 72 is driven, the driving shaft for turning 74 and the driving pulley 76 (refer to FIG. 4) rotate. Therefore, the endless belt 70 pulled by the driving pulley 76 begins to turn. Turning of the endless belt 70 is assisted by the three driven pulleys 78. That is, in this case, the endless belt 70 turns due to the driving pulley 76 and the three driven pulleys 78, while being applied with tension by the exterior tensioner 86 and being pressed by the pressing rod 100 from the inner peripheral belt 82 side.

Due to the above eccentric rotation of the polishing mechanism 16 and turning of the endless belt 70, polishing of the section-A 120 is started. That is, the endless belt 70 makes sliding contact with the section-A 120, thereby polishing the section-A 120. The endless belt 70 is applied with tension by being pressed from the exterior tensioner 86, hence the pressing force on the region-to-be-polished decreases. However, in the first embodiment, the pressing rod 100 configuring the pressing force applying mechanism 90 advances, whereby the endless belt 70 is pressed to the region-to-be-polished side. In other words, the endless belt 70 is pressed against the section-A 120. As a result, the endless belt 70 makes sliding contact with the section-A 120 with sufficient surface pressure, while eccentrically rotating, so the section-A 120 is favorably polished.

In this state, the control section 20 operates each of the shaft sections 26 of the articulated robot 12 in such a manner that the polishing mechanism 16 moves to the section-D 126 through the section-B 122 and the section-C 124. In the course of this, when the pressing force applying mechanism 90 has moved to the section-B 122 side by one row, the control section 20 performs supply/discharge of compressed air in such a manner that the pressing rod 100 advances or retracts according to the shape of the region-to-be-polished of the workpiece 22. However, the air cylinders 92 forming the lowest column, which is outside the region-to-be-polished, do not undergo supply/discharge of compressed air.

By supply/discharge of compressed air to/from the air cylinder 92, the pressing rod 100 advances or retracts. Furthermore, it is possible for the swinging cover 110 to swing. This is because, as described above, the engaging shaft section 109 of the ball joint 104 is fitted into the bearing hole of the swinging cover 110. In this way, by a combination of advancement or retraction of the pressing rod 100 and swinging of the swinging cover 110, a position of the pressing surface 114 of the swinging cover 110 changes according to the shape of the region-to-be-polished.

FIG. 7 shows one example of the position of the pressing surface 114 or attitude of the swinging cover 110 when a recess 132 is present in the region-to-be-polished. In this case, the pressing rod 100 of the air cylinder 92 positioned in an intermediate column advances more than the pressing rod 100 of the air cylinder 92 positioned below or above the intermediate column. It is therefore possible for the endless belt 70 to make sliding contact with a bottom section of the recess 132.

Contrarily, when the projection 130 is present in the region-to-be-polished, the endless belt 70 undergoes pressing from the projection 130, so the endless belt 70 is applied with further tension. Accordingly, the control section 20 performs supply/discharge of compressed air in such a manner that, as shown in FIG. 8, the pressing rod 100 of the air cylinder 92 positioned in the intermediate column retracts more than the pressing rod 100 of the air cylinder 92 positioned below or above the intermediate column. Therefore, tension acting on the endless belt 70 is relieved. Hence, an appropriate surface pressure is applied to the region-to-be-polished. As a result, the region-to-be-polished is prevented from being excessively polished. Note that in order to facilitate understanding regarding differences in advancement/retraction amount of the pressing rods 100 or differences in attitude of the swinging covers 110, FIG. 8 shows an example of the case where all of the pressing force applying mechanisms 90 enter the region-to-be-polished.

As described above, the surface pressure of the endless belt 70 when the endless belt 70 makes sliding contact with the region-to-be-polished is appropriately regulated by the control section 20 suitably advancing or retracting the pressing rods 100. Moreover, when the endless belt 70 deforms according to the shape of the region-to-be-polished, the swinging cover 110 swings. Therefore, deformation (expansion/contraction) of the endless belt 70 is never hindered. Hence, the region-to-be-polished can be favorably polished, regardless of the shape of the region-to-be-polished. Note that, even within the region-to-be-polished, when a place not requiring polishing is passed, it is also possible to cause the pressing rods 100 facing the place not requiring polishing to be retracted to the backward end.

When the polishing mechanism 16 reaches the section-D 126, rotation or revolution of each of the shaft sections 26 of the articulated robot 12 stops, and movement of the polishing mechanism 16 ends. At this time, the control section 20 stops both the motor for eccentric rotation 34 and the motor for turning 72, whereby eccentric rotation of the polishing mechanism 16 and turning of the endless belt 70 are stopped. The control section 20 further supplies compressed air to the cylinder tubes 98 other than the cylinder tubes 98 of a total of three columns, namely, the lowest column and the columns one and two above the lowest column, and maintains the pressing rods 100 in a forward end position.

As described above, in the first embodiment, a configuration is adopted such that by increasing a propelling force of the air cylinder 92 at the polishing start point (section-A 120) and the polishing end point (section-D 126) regardless of the shape of the region-to-be-polished, the region-to-be-polished is applied with a larger surface pressure compared to another region-to-be-polished. As a result, insufficient polishing at the polishing start point and the polishing end point is avoided. Moreover, since polishing can be performed automatically by the polishing device 10, a burden of an operator is reduced.

In this case, the endless belt 70 is turning, so an unspecific place of the outer peripheral belt 84 makes sliding contact with the region-to-be-polished. In other words, it is avoided that a specific place alone of the outer peripheral belt 84 is involved in polishing. Therefore, the outer peripheral belt 84 is not easily worn down. Hence, the same outer peripheral belt 84 can be employed over a long time. Note that when the outer peripheral belt 84 has worn down due to repeated polishing over a long time, and polishing accuracy has thereby lowered, the outer peripheral belt 84 may be replaced with a new one.

Next, a polishing device according to a second embodiment will be described. Note that constituent elements the same as constituent elements configuring the polishing device 10 according to the first embodiment will be assigned with the same reference symbols as those assigned in the first embodiment, and illustrations or detailed descriptions thereof will be omitted.

The polishing device includes a polishing mechanism 150 shown in FIG. 9. A supporting body 152 configuring the polishing mechanism 150 includes a coupling wall section 154 and a guide plate section 156. A coupling cylinder 157 is bridged between the guide plate section 156 and the coupling wall section 154. Moreover, as shown in detail in FIG. 10, the guide plate section 156 is provided with an insertion hole 158 through which the pressing rod 100 of the air cylinder 92 configuring a pressing force applying mechanism 159 is passed, and a fixture 160 provided to a tip of the cylinder tube 98 is housed in the insertion hole 158. The fixture 160 prevents the guide plate section 156 from falling off.

A plurality of (for example, two) guide holes 162 are formed in the guide plate section 156 at positions surrounding the pressing rod 100. Bushes 164 are respectively housed in the guide holes 162, and guiding rods 166 are passed through the bushes 164. A tip, of the guiding rod 166, provided with a screw section is passed through a through-hole 170 formed in a displacement plate 168, and then a nut 172 is screwed onto the tip. In addition, a tip of the pressing rod 100 is attached to the displacement plate 168. Hence, due to extension/contraction of the pressing rod 100, the displacement plate 168 is displaced, and the guiding rod 166 extends/contracts.

A stepped holder 174 having a step section is attached to the displacement plate 168. A screw hole is formed in a tip of the stepped holder 174, and the screw-shaped shaft section 106 of the ball joint 104 is screwed into the screw hole. Moreover, a separable swinging cover 180 is screwed onto and thereby attached to two engaging shaft sections 109 projecting from the ball section 108 of the ball joint 104.

A first holding rod 184 that holds a first roller 182 in a rotatable manner, and a second holding rod 188 that holds a second roller 186 in a rotatable manner are coupled to the supporting body 152.

A first coil spring 192 and a second coil spring 194 as a tension applying unit are hooked on hook sections 190 provided to the coupling wall section 154. Furthermore, a sheet body 196, which is a polishing body, is hooked on the first coil spring 192 and the second coil spring 194 to be held thereby. A predetermined tension acts on the sheet body 196 due to the first coil spring 192 and the second coil spring 194 contracting and due to the flat pressing surface 114 of the swinging cover 180 abutting on the sheet body 196.

The polishing device according to the second embodiment is basically configured so as to comprise: the polishing mechanism 150 configured as above; and the eccentric rotation mechanism 52 configured similarly to that of the polishing device 10 according to the first embodiment. Next, operation of the polishing device will be described.

In order to move the sheet body 196 along the region-to-be-polished in a state where the sheet body 196 has been abutted on the polishing start point of the workpiece 22, teaching is performed beforehand in the articulated robot 12 so that each of the shaft sections 26 rotates or revolves by a predetermined angle.

When starting polishing, the control section 20 supplies the air cylinder 92 with compressed air from the supply/discharge mechanism. The compressed air is introduced into the cylinder tube 98 via the supply/discharge tube 96, and presses the piston. As a result, the pressing rod 100 advances to the forward end, and the flat pressing surface 114 of the swinging cover 180 presses the sheet body 196, as shown in FIG. 11. Consequently, the sheet body 196 extends while being aided by making sliding movement relatively to the first roller 182 and the second roller 186. In addition, the first coil spring 192 and the second coil spring 194 extend, whereby a predetermined tension is applied to the sheet body 196.

The shaft sections 26 of the articulated robot 12 each suitably operate, and the sheet body 196 abuts on the polishing start point (section-A 120 in FIG. 6). Similarly to above, in the case where a projection 130 due to undulations or curvature is present in the section-A 120, the pressing force of the air cylinder 92 (the pressing rod 100) facing the projection 130 may be reduced, if required. This is achieved by discharging a small amount of compressed air from the cylinder tube 98 via the supply/discharge tube 96. By thus regulating (correcting) the pressing force from the pressing rod 100 according to the projection 130 of the section-A 120, the section-A 120 can be evenly polished.

Next, the control section 20 drives the motor for eccentric rotation 34 (refer to FIGS. 2 and 3). In association with the rotation of the driving shaft for eccentricity 36 of the motor for eccentric rotation 34, the driving gear 38 rotates, and the first driven gear 40 (refer to FIGS. 2 and 4) engaged with the driving gear 38 and the second driven gear 42 engaged with the first driven gear 40, rotate. Following this, the driven shaft for eccentricity 44 also rotates. Furthermore, the first rotating shaft for eccentricity 48 and the second rotating shaft for eccentricity 50 are driven to rotate, whereby the polishing mechanism 150 eccentrically rotates.

Due to the polishing mechanism 150 eccentrically rotating in this way, the sheet body 196 makes sliding contact with the section-A 120. Since the sheet body 196 makes sliding contact with the section-A 120 with sufficient surface pressure, while eccentrically rotating, the section-A 120 is favorably polished.

In this state, the control section 20 operates each of the shaft sections 26 of the articulated robot 12, and moves the polishing mechanism 150. In the course of this, the air cylinder 92 undergoes supply/discharge of compressed air, and the pressing rod 100 advances or retracts. Furthermore, the swinging cover 180 swings, and a position of the pressing surface 114 thereof changes according to the shape of the region-to-be-polished. Hence, even when the recess 132 or the projection 130 is present in the region-to-be-polished, an appropriate surface pressure is applied to the region-to-be-polished from the sheet body 196. Therefore, the region-to-be-polished can be accurately polished, regardless of the shape of the region-to-be-polished.

Note that, similarly to the polishing device 10 according to the first embodiment, the air cylinder 92 outside the region-to-be-polished between the polishing start point and the polishing end point may not undergo supply/discharge of compressed air.

When the polishing mechanism 150 reaches the polishing end point, rotation or revolution of each of the shaft sections 26 of the articulated robot 12 stops, and movement of the polishing mechanism 150 ends. At this time, the control section 20 stops the motor for eccentric rotation 34, and stops eccentric rotation of the polishing mechanism 150 and turning of the endless belt 70. The control section 20 further supplies compressed air to the cylinder tubes 98 other than the cylinder tubes 98 of a total of three columns, namely, the lowest column and the columns one and two above the lowest column, and maintains the pressing rods 100 in a forward end position.

Thus, operational advantages similar to those of the first embodiment are obtained also in the second embodiment.

Moreover, in the polishing mechanism 150, there is no need to turn the sheet body 196, so the motor for turning, pulleys, and so on, are rendered unnecessary. As a result, a simpler configuration may be adopted for the polishing mechanism 150.

The present invention is not particularly limited to the above-described first embodiment and second embodiment, and may be variously modified in a range not departing from the spirit of the present invention.

For example, in the second embodiment, the first coil spring 192 and the second coil spring 194 are adopted as the tension applying unit. However, a cylinder may be adopted instead.

Moreover, instead of the polishing mechanism 16, the polishing mechanism 150 may be arranged in the endless belt 70 to configure the polishing device 10.

Furthermore, polishing may be performed similarly to above except that the motor for eccentric rotation 34 is not operated (in other words, except that the polishing mechanism 16 is not eccentrically rotated). Also in this case, sufficient polishing is performed. As may be understood from this, the eccentric rotation unit, such as the motor for eccentric rotation 34, is not indispensable.

Further still, adjacent pressing force applying mechanisms 90 (or pressing force applying mechanisms 159) may be supported by the supporting body 60 (or the supporting body 152) in such a manner that the phases of the swinging covers 110 (or swinging covers 180) differ by 90°.

Moreover, the pressing force applying mechanisms 90 may be arranged in a so-called zigzag manner. 

What is claimed is:
 1. A polishing device that polishes an object-to-be-polished by an expandable or contractible polishing body, the polishing device comprising: a pressing force applying mechanism configured to apply a pressing force to the polishing body; and a supporting body configured to support the pressing force applying mechanism, the pressing force applying mechanism including an advancing or retracting section configured to advance or retract, and a swinging section provided in a swingable manner to a tip of the advancing or retracting section, the tip facing the polishing body, the polishing device further comprising a control section configured to control a propelling force applied to the advancing or retracting section.
 2. The polishing device according to claim 1, further comprising an eccentric rotation unit configured to eccentrically rotate the supporting body.
 3. The polishing device according to claim 1, further comprising a tension applying unit configured to apply a tension to the polishing body.
 4. The polishing device according to claim 1, wherein the advancing or retracting section advances or retracts, or the swinging section swings, according to a shape of the object-to-be-polished.
 5. The polishing device according to claim 1, further comprising a robot configured to hold the supporting body.
 6. The polishing device according to claim 1, wherein the advancing or retracting section is configured from an air cylinder having a rod.
 7. The polishing device according to claim 1, wherein the polishing body is an endless belt configured to turn, and the polishing device comprises a driving force applying unit configured to apply, to the endless belt, a driving force for turning.
 8. The polishing device according to claim 1, wherein the polishing body is a sheet body hooked to the supporting body.
 9. The polishing device according to claim 1, wherein the control section sets the propelling force applied to the advancing or retracting section at a polishing start point and a polishing end point for the object-to-be-polished larger than the propelling force applied to the advancing or retracting section at another region-to-be-polished.
 10. The polishing device according to claim 7, wherein the endless belt is a stacked body of an inner peripheral belt positioned on an inner peripheral side and an outer peripheral belt positioned on an outer peripheral side.
 11. The polishing device according to claim 6, wherein the air cylinder is provided in plurality, and the control section does not supply or discharge compressed air to or from an air cylinder outside a region-to-be-polished between a polishing start point and a polishing end point, among the air cylinders. 